This invention relates in general to packaging machinery and more particularly to a method and machine for automatically taking a continuous hollow web of a thin plastic material, directing it through a cutter to slice the web transversely forming individual segments, and to move said segments over a container, such as a bottle, where the segment can subsequently be shrink-wrapped.
There have been a wide number of techniques developed for performing operations, in the shrink-wrapping of band labels for containers. These techniques have been employed to form, around a container, individual band sleeves from a continuous roll of a flattened tubular web of thin flexible plastic. A suitable apparatus provides for opening the tube to slip it over the container and to provide means for cutting off an individual label for each container. The usual automatic arrangement includes a table top conveyor to provide the container either in a continuous motion or intermittent motion to a work station where the shrink wrap band is placed over it. The conveyor then carries the banded container to another work station for performing the shrink operation itself. There are at least two critical characteristics that such a system must have. One is that it operate at relatively high speed so that the through-put of the operation is economical. A second is that it be relatively free of jams so that production does not get interrupted.
Much of the development in the art has focused on the problem of how to open the tube or web for placement over the container and how to cut or slice the web transversely while still maintaining a driving force for the web after it has been segmented to carry it over the bottle. Generally, it has not proven feasible to cut the web in an open or partially open position. Thus much of the art has been directed towards the use of blowers, vacuum and the like to open the tubular web after it has been cut and also to a means for carrying the cut segment of the tubing in the open condition over the container, or other object being banded.
One device which has been used frequently as one element in such a banding apparatus is referred to as a "floating mandrel" which provides for defining the tube in an open shape and to provide means for placing that open shape over the container. In one approach the web is cut at a point overlying the mandrel by a razor edge which circumscribes the web on the mandrel. Another approach has been to sever the web segment while it is in the bottle, either by using a perforated web and breaking it at the perforation line, or cutting the continuous web at a point just above the top of the bottle.